Pipe thread protector



April -6, 1943. 4 Ti N 2,316,013

. PIPE THREAD PROTECTOR Filed march 22, 1941 2 Sheets-Sheet 1 say. 2.

April 6, 1943. 'r. MULHOLLAND 2,315,013

' PIPE THREAD rnowscwon 7 Filed March 22. 1941 '2 Shets-Sheefi 2 Patented Apr. 6, 1943 UNITED STATES PATENTOFFICE PIPE THREAD PROTECTOR Thomas Mulholland, Pittsburgh, Pa.

Application March 22, 1941, Serial No. 384,749

3 Claims.

The present invention relates in general to pipe-thread protectors and more particularly to that type of protector in which a relatively soft, compressible liner sleeve in contact with the threads is compressed against the threads to be protected by a clamping ring or sleeve, through the intermediation of an intervening variable diameter, pressure-distributing sleeve.

An important object of the present invention is the provision of a protector of the above type which may be readily applied and removed at will while highly resistant to accidental dislodgement or injury through even extremely careless and rough handling such as is frequently encountered in shipping and storing.

A further object is to provide a protector having the above qualities which shall be simple in construction and practically self-explanatory of its use, and easily understood by ordinary handlers without special instruction in its use.

Another object looking to simplicity and sturdiness of construction is the provision of a clamping sleeve or ring capable of being held strongly in place against forceful displacement and readily removed without the use of hinged parts, latch mechanism or like contrivances subject to injury through rough handling;

Another object is the provision in a three part thread-protector of the present type, of a variable diameter sheet metal, pressure distributing sleeve capable of having its diameter varied substantially evenly throughout the length of its contact with the liner sleeve sufliciently to effect the desired compression of the liner without undue buckling or other permanent distortion of its structural parts.

Another object of the invention is to provide 'for a retaining of the parts of the protector in an orderly arrangement for simultaneous handling and application of all three parts of the protector to a pipe end in proper order, whereby mistakes in the order of assembling the parts on a pipe end are avoided.

The above, and various other objects and advantages of the invention will be more clearly understood from a perusal of the following specification and the drawings accompanying the same.

In the drawings:

Figure 1 is a side elevation, partly in section, of the protector for external threads, with its three parts separated and arranged co-axially in the order of their assembly.

' Figure 2 is a side elevation of the same, partly insection, as held in partly assembled position about to be applied to a pipe end.

Figure 3 is aside elevation of a threaded end of a pipe showing the protector applied thereto, the protector being shown in axial section.

Figure 4 is a side view, partly in section, of the protector for internal threads, with the three parts separated and arranged co-axially in the order of their assembly.

Figure 5 is a side elevation of the same, partly in section, as held in partly assembled position about to be applied to the inside threads of a pipe end.

Figure 6 is an axial section of the protector for internal threads, clamped within the internally threaded end of a pipe.

Referring to the drawings in detail and first to Figures 1 to 3', these show a preferred form of my improved pipe-thread protector for an externally threaded pipe end. As is illustrated in Figure 1, the device comprises the three elements, a liner sleeve III, a variable-diameter, pressure distributing sleeve H, and a clamping cap or sleeve l2. The liner sleeve H! which is composed of a suitable compressible material such as rubber, felt, cork or the like is shaped and proportioned to slide over onto the threads |3 formed on the end of a pipe I 4 as indicated in Figures2 and 3. In accordance with common practice the threaded end of the pipe is usually slightly tapered, wherefor the sleeve I0 is made slightly conical to substantially conform to the general contour of the threaded pipe-end. However, because of the conformability of the material of which the liner sleeve is made, this sleeve may be made in the form of a substantially straight cylinder with the economical advantage that any of various existing kinds of tubing of compressible material of substantially the desired diameter and Wall thickness, may be used thus avoiding necessity for original production of this element of the device leaving requirement for original production of the metal parts only.

The pressure-distributing sleeve II, of slight conical form, is composed of a plurality of separate plates IS in the form of sectors of a cone. The plates I5 are held in a circular group and slightly circumferentially spaced from each other by a relatively thick, rigid mounting ring I6 to which the plates are secured each at one end by means of integral tabs ll bent around the mounting ring. The mounting ring'lfi is made with a diameter and thickness suflicient to overlie a sub stantial portion of the pipe rim so as to form, together with the bent tabs, a radially inwardly extending shoulder on the sleeve H for engagement with the end of the pipe. The plates 15 are preferably loosely secured to the ring and the tabs ll made sufficiently numerous and narrow to permit them to be readily bent around this mounting ring and to permit substantial movement of the plates l5 toward and away from the axis of the sleeve without necessity for substantial deformation of the plate or tabs. This makes for a minimization of the resistance to a collapsing of the sleeve itself, thus reducing the total force required for collapsing of the sleeve H and compression of the liner sleeve against the pipe threads. Thus constructed the sleeve ll forms a cone of slight taper proportioned and arranged to telescope over the conical liner. sleeve it, as shown in Figure 2, with the mounting ring it offset inwardly to abut'the adjacent run of the liner sleeve and act as a stop to limit their relative telescopic movement.

The clamping ring or sleeve I2. is also in the form of a cone of slight taper and so proportioned with respect to the other sleeves l0 and i i that when forced into closed telescopic relation with the latter sleeves and the threaded pipe end, it will reduce the diameter of the pressure distributing sleeve H sufliciently to compress the liner sleeve against and into or partly into the threads 93 on the pipe end. At its outer rim, the clamping sleeve is provided with an inwardly extending flange which acts as a stop shoulder to limit the telescopic movement of the clamping sleeve over the pressure sleeve and to afford a widened rim area for engagement with a suitable driving-on tool such as a wide face mallet or the contact plate of a pressing-on tool. With a completed assembly of the protector on a threaded pipe-end as indicated in Figure 3, the liner sleeve I!) iscompressed firmly against the threads l3 by the forcibly wedged-on clamping sleeve ll through the intermediation of the pressure distributing sleeve l2.

With the object of assuring substantially high compression of the liner sleeve and a strong clamping hold of the clamping sleeve l2 upon the pressure distributing sleeve ll sufficient to resist dislodgement of the clamping sleeve by rough handling, the latter is made in the form of a continuous, solid walled cone of relatively thick gauge compared to the gauge of the metal used in the compression sleeve H. To enable the use of a strong, thick-walled clamping ring resistant to dislodgement or injury by even severe blows, which at the same time may be readily removed at will, I provide the clamping sleeve with a scored strip portion l8 formed in its wall by the parallel scored grooves l9 substantially the entire length of the sleeve and provided with a tab 2i! extending beyond one end of the sleeve by means of which the scored strip may be sheared out or partly out of the clamping sleeve to release the latter.

To provide for maintaining together and in readily useable arrangement a complete set of parts constituting a protector, the protectors as furnished to the users are arranged with their three sleeves in partially assembled position ready for application to a threaded pipe-end without necessity for further arrangement of parts, as is shown in Figure 2, where it will be seen the liner sleeve H] is completely nested in the pressure-distributing sleeve H, and the clamping sleeve lZpartially telescoped onto the sleeve H sufhciently to bring the latter two into close contact without substantial contraction of the sleeves H3 and H. The metallic sleeves II and I2 are temporarily held in this position against accidental dislodgement during storage and handling up to the time of use, by a suitable frangible means preferably alight spot of solder joining the two at points as indicated at 32. While friction may be relied upon to hold the liner sleeve in place, it is preferable to cement the latter to the sleeve I I at points with a holding strength sufficient to prevent accidental dislodgement but insufficient to prevent relative movement between the two necessary to permit proper distribution of pressure between them.

Referring now to Figures 4 to 6, here is shown a. modification of the device for use with internal threads, wherein the functional relation of the parts are substantially the same, but their radial disposition is reversed. In this form of the device the liner sleeve 2| is of conical form with a slight taper conforming to that of the internally threaded portion to be protected, in the present case the threaded portion 22 of the pipe 23. The pressure-distributing sleeve 24 is I of a construction similar to that of the external-thread protector except that its mounting ring 25 extends radially outwardly of the plate elements 26 while the latter are loosely attached to the ring by integral tabs 2'! looped radially outwardly of the plates around the mounting ring. Here, as in the formerly described modification, the plate elements are in the form of sectors of a cone and are held by the ring 25 in a circular group circumferentially spaced and independently movable toward and away from the axis of the group to permit variation in the diameter of the sleeve without substantial deformation of the plates or tabs. The'mounting ring 25 is made with a diameter such that together with the embracing tabs 21 it will form an outwardly extending shoulder for engagement with the side of the outermost thread to act as a stop to the telescopic movement of the pressuredistributing sleeve 24 into the liner sleeve 2|. As an alternative, the mounting ring 25 may be made of a diameter sufficient to extend the assemblage of the plates 26 and the tabs 2'! a distance suflicient to overlie the outer rim 28 of the pipe.

The clamping sleeve 29, in this case, is a simple conical sleeve of slight taper to substantially parallel the taper of the threads to be protected, and proportioned and arranged to be forcibly telescoped into the pressure-distributing sleeve to compress the liner sleeve against the threads through the intermediation of the pressure-distributing sleeve. The protector thus assembled in the internally threaded end of a pipe is shown in Figure 6. As indicated in Figure 5, the clamping sleeve 2% is provided with a scored strip portion 30 formed by the parallel grooves or scorings 3! extending the length of the sleeve, which scored strip may be readily sheared away from the clamping sleeve to release the latter and permit its removal, and removal of the remainder of the protector. Inasmuch as the protector of Figures 4 to 6 is used internally of the pipe where it is less subject to injury in handling and where the stresses on the compression sleeve are directed radially inwardly of the sleeve, the latter may be made of relatively thin gauge metal compared with that of the pressure sleeve used in the external thread protector. In. thecase of an inside-thread protector, it is also contemplated to use in place of the scored, solid clamping sleeve 29, a collapsible split sleeve of strong,

sheet, spring metal normally of a larger diameter than the pressure-distributing sleeve 24 so as to exert the desired pressure thereagainst when telescoped therein.

While I have herein shown and described cer tain specific embodiments of my invention for the sake of disclosure, it is to be understood that the invention is not limited to such specific embodiments, but contemplates all such modifications and variants thereof as fall fairly within the scope of the appended claims.

What is claimed is:

1. A pipe-thread protector comprising a liner sleeve of compressible material arranged to be slid over the threads to be protected, a variablediameter pressure-sleeve composed of separate circumferentially spaced plates held assembled in the form of a sleeve by attachment each at one end to a mounting ring and arranged to telescope over the surface of the liner sleeve opposite the threads to be protected, and a clamping sleeve arranged to be forced into clamping telescopic relation with the pressure sleeve to vary the diameter of the latter and cause the latter to compress the liner sleeve against the threads to be protected.

2. A pipe-thread protector comprising a liner sleeve of compressible material arranged to be slid over the threads to be protected, a relatively thick, non-collapsible mounting ring, a circular series of separate relatively thin, circumferentially spaced plates each loosely attached at one end to the ring and extending axially therefrom to form a variable diameter pressure sleeve adapted to telescope with the liner sleeve, said mounting ring being proportioned to overlie at least a portion of the rim of the threaded end of the pipe and the attached ends of said plates being offset to provide a shoulder to engage the adjacent end of the compressible sleeve liner, and a clamping sleeve proportioned to slide into Wedging telescopic relation with the pressure sleeve to vary the diameter of the latter and cause the latter to compress the liner sleeve against the threads to be protected.

3. In a pipe-thread protector the combination of a liner sleeve of compressible material, a substantially rigid conical clamping sleeve, an intervening, variable diameter, compression sleeve, and frangible holding means, said sleeves being held in extended telescopic relation by the frangible means and arranged to be forced into closed, wedging, telescopic relation against the holding effect of the frangible means to vary the diameter of the compression sleeve and cornpress the liner sleeve against the threads to be protected.

THOMAS MULI-IOLLAND. 

